1. Field of the Invention
The present invention relates to a cushion structure used as a seat cushion or backrest of various seats and to a manufacturing method and apparatus of the cushion structure.
2. Description of the Prior Art
Disclosed in Japanese Patent Laid-open Publication No. 11-290153 is a cushion structure the surface of which is formed with a square net rolled up on a metallic square frame at each side end portion thereof and stretched on the frame by adhered thereto. The cushion structure is superior in elastic cushion property in a simple construction since the resiliency of the stretched net is useful to enhance the cushion property of the structure without causing a hardness feeling and a bottomed feeling. Accordingly, the cushion structure can be used as a seat cushion or backrest of various seats. However, the cushion property of the structure is influenced in dependence upon only the resiliency of the stretched net.
During the manufacturing process of the cushion structure, a square die formed with a square groove corresponding with the configuration of the frame is used for setting thereon the square net in place. In a condition where the square net was set on the die, the square frame is coupled with the corresponding square groove of the die so that the square net is rolled up on the square frame at each side end portion thereof and adhered to the square frame in place by thermoplastic resin in a melted condition. When the square frame is coupled with the corresponding square groove of the die, the whole portion of the square net except for each side end portion is brought into contact with the surface of the die surrounded by the square groove and restricted in a stretched condition. With such a setting method, it is difficult to uniformly adjust the tension of the square net in a desired value.
It is, therefore, a primary object of the present invention to provide a cushion structure in which a quadrilateral or square (hereinafter the two terms are simply stated as xe2x80x9csquarexe2x80x9d) frame of combined structure composed an elastic frame body and a hard frame body embedded in the elastic frame body is used to enhance the cushion property of the structure by combination of the resiliency of the stretched net and the resiliency of the elastic frame body.
A secondary object of the present invention is to provide a method and apparatus suitable for manufacturing the cushion structure in a simple manner.
According to the present invention, the object is accomplished by providing a cushion structure used as a seat cushion or backrest of a seat, comprising a square net stretched on a square frame of combined structure composed of an elastic square frame body and a hard square frame body embedded in the elastic square frame body, wherein each side end portion of the square net is rolled up on the elastic square frame body of the square frame and fastened to the hard frame body of the square frame. In the cushion structure, it is preferable that a mounting plate adhered to each side end portion of the square net is fastened to the hard square frame body.
According to an aspect of the present invention, there is provided a manufacturing method of a cushion structure the surface of which is formed with a square net rolled up on a square frame at each side end portion thereof and stretched on the square frame by fastened thereto, wherein the manufacturing method comprises the steps of retaining a square net on a support bed in a flat condition, placing a square frame combined structure in position on the square net retained on the support bed, the square frame being composed of an elastic square frame body and a hard square frame body embedded in the elastic square frame body, pressing the square frame of combined structure toward the square net to roll up each side end portion of the square net on each frame portion of the elastic square frame body of the square frame, and fastening each side end portion of the square net to the hard square frame body of the square frame.
According to another aspect of the present invention, there is provided a manufacturing apparatus of a cushion structure the surface of which is formed with a square net roller up on a square frame at each side end portion thereof and stretched on the square frame by fastened thereto, wherein the manufacturing apparatus comprises a square support bed for retaining a square net thereon in a flat condition, a plurality of clamping mechanisms mounted on the support bed for clamping each side end portion of the square net retained on the support bed, and a plurality of pressure mechanisms mounted on the support bed for pressing a square frame placed on the square net clamped by the clamping mechanisms so that each side end portion of the square net is rolled up on each frame portion of the square frame.